1. Field
The present invention generally relates to rack-mounted computer systems, and more particularly relates to cable-arm assemblies used with rack-mounted computer systems.
2. Description of the Related Art
Computer systems are often mounted in rack-mounted structures. Rack-mounted structures enable computer components to be installed vertically, taking up less floor space in a computer operations area. Multiple rack-mounted structures can be installed in a computer area allowing for growth and flexibility of the components installed. Rack-mounted structures are typically vertical with individual components mounted in with side mounted slides that attach to the rack. The individual components can then be slid into and out of the rack. In this manner, the individual components can be accessed for repairing the unit, providing upgrades, configuring the unit, connecting the unit to other components, and other tasks.
Rack-mounted systems are typically air-cooled so ventilation is provided by having air pass through the individual components, often through the individual component from the front of the component to the back of the component. In this way, other components above and below the individual component will not block the air flow through the unit.
Some of the individual components often included in a rack system include servers, other computers, and direct access storage devices, such as disk drives and RAID subsystems. Access to components is provided by the slidable structure attached to the internal frame portion of the rack. In this way, components can be moved to a forwardly extended component access position for servicing. When not being serviced, the component is moved to a rearwardly retracted operating position.
Each component generally has a variety of cables attaching the component to power sources, communication networks, and other components. Each component generally has at least one power cable which provides power to the component's power supply. Components also have cables connecting the unit with other components both inside and outside the rack. For example, a typical computer system component connects to a video display device for an operator to view the operation of the computer system, a printer for printing, a network adapter for communicating with other computer systems on a local area network (LAN), a modem for connecting to other computers over the telephone system, external storage devices such as disk drives, RAID drives, optical disks, and tape drives. Each of these connections usually involves attaching a cable to the component. These connections are usually made at the back of the unit by connecting the cable to connectors provided on interface cards installed in the computer or connectors provided on the back of the individual component.
All these connections can lead to a large quantity of cables connecting to individual components as well as large numbers of cables within the rack. The components in the rack slide to a forwardly extended component access position and slide back to a rearwardly retracted operating position, cables are extended to an additional length so the component can be slid to the forwardly extended component access position without the cables snagging or becoming removed from the component. Likewise, when a particular component is moved to the rearwardly retracted operating position, the excess length of cables needs to be handled so that they do not become entangled with cables attached to other components above and below the particular component.
Cable arms are often provided to provide a structure to which the cables are fastened. FIG. 1 shows a prior art cable arm 100 which is commonly used. Prior art cable arm 100 includes a first prior art segment 110 and a second prior art segment 120. Prior art hinge 130 attaches first prior art segment 110 to second prior art segment 120 so that when component 140 is in the rearwardly retracted operating position, prior art hinge 130 allows the back of first prior art segment 110 to be substantially flat against the back of second prior art segment 120. A hinge attaches first prior art segment 110 to rack 160 while prior art hinge 170 attaches second prior art segment 120 to component 140. Cables 150 attach to component 140, extend along front side of second prior art segment 120, wrap around prior art hinge 130, and extend along front side of first prior art segment 110 before reaching the back of rack 160.
Prior art cable arm 100 allows component to be forwardly extended to a length not exceeding the length of prior art cable arm 100. Prior art cable arm 100 in turn is limited to a maximum length of twice the interior width of rack 160. A challenge in the use of prior art cable arm 100 is a difficulty encountered in extending component 140 enough to adequately work on a component. Adding additional segments to prior art cable arm 100 poses additional challenges as additional hinged segments restrict cables 150 from wrapping from segments 110 and 120 to additional segments. Another challenge is encountered when the arm is extended by adding segments without greatly increasing the depth taken by prior art cable arm 100 in rack 160 when the component is in the rearwardly retracted operating position. Limited space is often provided between the back of component 140 and the back of rack 160. This limited amount of space may prohibit a deeper cable arm with additional segments from being used because component 140 would not be able to completely reach a rearwardly retracted operating position.
It is desirable to provide a longer cable arm without greatly increasing the depth of the cable arm. It is further desirable to allow cables to wrap from segment to segment with minimal restriction.